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Closer look at Northern Gateway pipeline construction

While Enbridge's $7 billion Northern Gateway pipeline project must overcome many political and bureaucratic challenges before the oil can flow, logistical challenges from its actual construction are also being mulled over.

The joint review panel, commissioned by the federal government to investigate the effects of pipeline construction, detailed Enbridge’s tentative building plans in its report.

Here’s how Enbridge plans to build the pipeline.

The proposed plan runs 1,177 kilometres of parallel pipelines from near Edmonton to Kitimat on the northern coast of B.C.

So how did Enbridge decide upon on Kitimat? According to the panel, the company investigated several other pipeline routes and West Coast ports, and went through 22 revisions before choosing the current Kitimat route.

One route that nearly made the cut was to Prince Rupert.

It was scrapped because Kitimat is safer, has fewer environmental concerns and is cheaper.

Pipelines to Prince Rupert would be longer, encounter greater risks from landslides and avalanches and would have to span the Skeena River.

The B.C. section of the proposed pipeline is about 660 kilometres while the Alberta portion is about 520 kilometres.

About half of the Alberta portion of the route would cross private land and half would cross provincial or federal Crown lands.

More than 90 per cent of the British Columbia portion of the route would be on provincial Crown lands.

Much of the route would also cross through areas used by Aboriginal groups

The plans are subject to approval by the National Energy Board and other regulators.

The process includes numerous environmental and technical surveys and consultation with Aboriginal groups and affected populations.

The construction would be divided into 12 “spreads.”

These are sections of the pipeline built by a single prime contractor.

Work camps are planned at 11 sites on the pipeline route where 500 to 940 workers would stay. Kitimat would also have a camp for around 230 people working on the oil tanker terminal and laying pipe in the Kitimat Valley area.

According to the panel, Enbridge’s pipes would be about 20 per cent thicker than Canadian standards. The thickness varies along the pipeline depending on pressure and the environment it’s in.

The minimum wall thickness would be 19.8 millimetres on the oil pipeline and 7.1 millimetres on the condensate pipeline.

The pipe would also have a protective coating put on before arriving at the site, and another coating would be put over weld areas before placing the pipe into the trench.

Northern Gateway told the panel it plans to seed or plan the 25-metre-wide permanent right-of-way with native vegetation wherever possible after construction is complete.

The additional 25-metre-wide temporary work area used during construction would be returned as close as possible to its previous state.

Crews would also reclaim some roads, while other roads would be kept open for ongoing maintenance and emergency response. Power lines would be built to serve the pumping stations.

Northern Gateway said it would work with groups to salvage cut timber when possible. It also plans to plant trees in reclaimed work areas and elsewhere to compensate for forest removal on a tree-by-tree and hectare-by-hectare basis.

Enbridge also told the panel it plans to work, whenever possible, during times of the year that would least affect people, wildlife, land and water resources.

Enbridge plans to avoid avalanche and landslide risks in the Coast Mountain Range by building two tunnels roughly 50 kilometres from Kitimat. The tunnels will be located between the Clore River valley on the east side of North Hope Peak and the Hoult Creek valley on the west side of Nimbus Mountain. The east tunnel is referred to as the Clore tunnel and the west tunnel is referred to as the Hoult tunnel.

The tunnels would each be about 6.5 kilometres long and would be large enough to provide access for maintenance and emergency response. Northern Gateway told the panel that protective barriers or deeper burial would shelter the pipelines in other areas subject to potential slides.

The tunnels will be built using drilling, blasting or boring. It is estimated tunnel construction could take three years.

There are more than 1,200 watercourses the route crosses, though many of the smaller ones have little or no flow, and don’t have fish.

The smaller ones would be crossed by digging a trench and laying pipe.

On larger fish-bearing bodies of water, workers would use horizontal directional drilling or boring underneath to avoid disturbing the water or its banks.

Other measures, like screens and bubble curtains, would contain silt during construction of the Kitimat Terminal.

The terminal would also have berms and containment areas to prevent oil or contaminated water from reaching Douglas Channel in the event of a spill.

Enbridge also plans to line trenches with limestone to neutralize acid run-off from sulphide bearing rocks.

This is also a concern for the tunnel construction. Enbridge responded to the panel by saying it would separate the sulphide rocks and deal with them to prevent runoff.

Northern Gateway told the panel that construction and operations would cause minimal rises in total suspended solids concentrations and would not hurt water quality or affect drinking water.

Erosion control methods, sediment traps and vegetation cover are some of the measures it plans to use to combat this.

As for the Kitimat facility, custom-designed harbour and escort tugs would be built. In addition, Northern Gateway stated it would fund new radar and navigational aids.

The Canadian Hydrographic Service is also updating several charts of the area to ensure the most accurate information would be available for safe navigation